Systems and methods for joining node and tube structures

ABSTRACT

Connections between nodes and tubes are provided. An apparatus can include additively manufactured first and second nodes, a tube, and an interconnect connecting the tube to the first and second nodes. An apparatus can include a node having an end portion with inner and outer concentric portions forming an annular gap therebetween, and a tube having an end portion extending into the gap.

BACKGROUND Field

The present disclosure relates generally to connections betweenstructures, and more particularly, to connections between nodes andtubes.

Background

Space frame and monocoque construction are both used in automotive,structural, marine, and many other applications. One example of spaceframe construction can be a welded tube frame chassis construction,often used in low volume and high performance vehicle design due to theadvantages of low tooling costs, design flexibility, and the ability toproduce high efficiency structures. These structures require that tubesof the chassis be connected at a wide variety of angles and may requirethe same connection point to accommodate a variety of tube geometries.Traditional methods fabrication of joint members for connection of suchtube frame chassis may incur high equipment and manufacturing costs.Additionally, monocoque design may lead to design inflexibility whenusing planar elements, or high tooling costs when shaped panels areincorporated.

SUMMARY

Several aspects of node-tube connections will be described more fullyhereinafter.

In various aspects, an apparatus can include additively manufacturedfirst and second nodes, a tube, and an interconnect connecting the tubeto the first and second nodes.

In various aspects, an apparatus can include a node having an endportion with inner and outer concentric portions forming an annular gaptherebetween, and a tube having an end portion extending into the gap.

Other aspects will become readily apparent to those skilled in the artfrom the following detailed description, wherein is shown and describedonly several embodiments by way of illustration. As will be realized bythose skilled in the art, concepts herein are capable of other anddifferent embodiments, and several details are capable of modificationin various other respects, all without departing from the presentdisclosure. Accordingly, the drawings and detailed description are to beregarded as illustrative in nature and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of will now be presented in the detailed description byway of example, and not by way of limitation, in the accompanyingdrawings, wherein:

FIG. 1 shows an exemplary vehicle chassis, Blade supercar chassis, inwhich aspects of the disclosure may be implemented.

FIGS. 2A-E illustrate exemplary nodes, tube, interconnect, and sealsthat form a joint.

FIGS. 3A-D illustrate exemplary nodes, tube, and interconnect that forma joint.

FIGS. 4A-D illustrate exemplary nodes, tube, interconnect, and sealsthat form a joint including a double-shear connection.

FIGS. 5A-C illustrate other exemplary nodes, tube, and interconnect thatform a joint.

FIGS. 6A-D illustrate an exemplary node including a connection portionto connect to a tube to form a joint.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appendeddrawings is intended to provide a description of various exemplaryembodiments of the concepts disclosed herein and is not intended torepresent the only embodiments in which the disclosure may be practiced.The term “exemplary” used in this disclosure means “serving as anexample, instance, or illustration,” and should not necessarily beconstrued as preferred or advantageous over other embodiments presentedin this disclosure. The detailed description includes specific detailsfor the purpose of providing a thorough and complete disclosure thatfully conveys the scope of the concepts to those skilled in the art.However, the disclosure may be practiced without these specific details.In some instances, well-known structures and components may be shown inblock diagram form, or omitted entirely, in order to avoid obscuring thevarious concepts presented throughout this disclosure.

A node is an additively manufactured (AM) structure that includes afeature, e.g., a socket, a receptacle, etc., for accepting anotherstructure, e.g., a tube, a panel, etc. This disclosure focuses onattachment designs for connecting the various parts of the node-basedassembly. Some interconnection designs are devised primarily to accountfor the higher levels of dimensional tolerance acceptance that may beencountered when assembling the complex structures. Some designs arealso constructed with the intent of reducing weight, minimizingpost-processing involved, and maximizing ease of assembly. Recurringcomponents of these ideas are using sockets to adjust for tolerance andco-printing parts to utilize the uniqueness of 3-D printing and simplifythe assembly process. For each method, a brazing slurry, athermoplastic, a thermoset, etc., may be used in place of an adhesive.

FIG. 1 illustrates an exemplary car chassis, i.e., Blade supercarchassis 100 built by Divergent Technologies, Inc., that includes nodesand tubes as part of the structure. Automobile chassis, such as Bladesupercar chassis 100, are examples of structures in which aspects of thedisclosure can be practiced. Although the examples described herein aredirected primarily to vehicle structures, such as chassis, crush zones,etc., it should be understood that aspects of the disclosure can beapplied to other structures that include node-tube connections.

Blade supercar chassis 100 includes carbon fiber tubes 101 connected byone or more nodes 103. Each node 103 can include, for example, a centralbody and one or more ports that extend from the central body. In variousembodiments, a multi-port node may be provided to connect tubes, such ascarbon fiber tubes 101, to form a two or three-dimensional structure.The structure may be a frame, for example. In one example, a structurehaving tubes with axes in substantially the same plane can be referredto as a planar frame, while a structure having tubes with axes indifferent planes may be referred to as a space frame. A space frame maydefine a volume. In some examples, a three-dimensional space framestructure may be a vehicle chassis. The vehicle chassis may be have alength, width, and height that define a space, such as a passengercompartment of the vehicle.

A vehicle chassis may form the framework of a vehicle. A vehicle chassismay provide the structure for placement of body panels of a vehicle,such as door panels, roof panels, floor panels, or any other panelsforming the vehicle enclosure. Furthermore the chassis may be thestructural support for the wheels, drive train, engine block, electricalcomponents, heating and cooling systems, seats, storage space, etc. Avehicle may be a passenger vehicle, a cargo vehicle, etc. Examples ofvehicles may include, but are not limited to sedans, trucks, buses,vans, minivans, station wagons, RVs, trailers, tractors, go-carts,automobiles, trains, or motorcycles, boats, spacecraft, or airplanes(e.g., winged aircraft, rotorcraft, gliders, lighter-than-air aerialvehicles). The vehicles may be land-based vehicles, aerial vehicles,water-based vehicles, or space-based vehicles. Any description herein ofany type of vehicle or vehicle chassis may apply to any other type ofvehicle or vehicle chassis.

The vehicle chassis may provide a form factor that matches the formfactor of the type of vehicle. Depending on the type of vehicle, thevehicle chassis may have varying configurations. The vehicle chassis mayhave varying levels of complexity. In some instances, athree-dimensional space frame may be provided that may provide an outerframework for the vehicle. The outer framework may be configured toaccept body panels to form a three-dimensional enclosure. In some cases,inner supports or components may be provided. The inner supports orcomponents can be connected to the space frame through connection to theone or more joint members of the space frame. Different layouts ofmulti-port nodes and connecting tubes may be provided to accommodatedifferent vehicle chassis configurations. In some cases, a set of nodescan be arranged to form a single unique chassis design. In some cases,at least a subset of the set of nodes can be used to form multiplechassis designs. In some cases at least a subset of nodes in a set ofnodes can be assembled into a first chassis design and then disassembledand reused to form a second chassis design. The first chassis design andthe second chassis design can be the same or they can be different.

In this example, carbon fiber tubes 101 are carbon fiber material. Invarious implementations, other composite materials may be used. Examplesof composite materials include high modulus carbon fiber composite, highstrength carbon fiber composite, plain weave carbon fiber composite,harness satin weave carbon composite, low modulus carbon fibercomposite, low strength carbon fiber composite, etc. In someimplementations, the tubes may be formed from other materials, such asplastics, polymers, metals, metal alloys, etc. The tubes may be formedfrom rigid materials. The tubes may be formed of one or more metaland/or non-metal materials.

The connecting tubes may have different cross-sectional shapes. Forexample, the connecting tubes may have a substantially circular shape,square shape, oval shape, hexagonal shape, or an irregular shape. Theconnecting tube cross-section could be a closed cross-section. Theconnecting tube cross-section could be an open cross-section, such as aC-channel, an I-beam, an angle, etc.

The tubes may be hollow tubes. A hollow portion may be provided alongthe entire length of the tube. For example, the connecting tubes mayhave an inner surface and an outer surface. An inner diameter for thetube may correspond to an inner surface of the connecting tube. An outerdiameter of the tube may correspond to an outer diameter of theconnecting tube. A connecting tube may have two ends. The two ends maybe opposing one another. In some embodiments, the connecting tubes mayhave three, four, five, six or more ends.

Various aspects of node-to-tube connections presented in this disclosuremay be suitable for use in a vehicle chassis frame such as Bladesupercar chassis 100 shown in FIG. 1. The nodes in the chassis frame 100may be designed to fit the tube angles dictated by the chassis design.The nodes may be fabricated to desired geometries to permit rapid andlow cost assembly of the chassis. In some embodiments the nodes may befabricated using 3-D printing techniques. 3-D printing may permit thenodes to be formed in a wide array of geometries that may accommodatedifferent frame configurations. 3-D printing may permit the nodes to beformed based on a computer generated design file that includesdimensions of the nodes.

A node may be composed of a metallic material (e.g. aluminum, titanium,stainless steel, brass, copper, chromoly steel, iron, etc.), a compositematerial (e.g. carbon fiber, etc.), a polymeric material (e.g. plastic,etc.), a combination of these materials and/or other materials, etc. Thenode can be formed from a powder material. The nodes may be formed ofone or more metal and/or non-metal materials. The 3-D printer can meltand/or sinter at least a portion of the powder material to form thenode. The node may be formed of a substantially rigid material.

FIGS. 2A-E, 3A-D, 4A-D, 5A-C, and 6A-D illustrate exemplary node-tubejoints (a.k.a., connections). FIGS. 2A-E, 3A-D, 4A-D, and 5A-Cillustrate techniques in which first and second nodes can be joined to atube with an interconnect connecting the tube to the first and secondnodes. FIG. 6A-D illustrates a technique in which a node can be joinedto a tube. In various embodiments, the joining can result in a smooth,flat surface that has an appealing look and that reduces the need forpost-processing, such as sanding, finishing, etc. In this way, forexample, nodes and tubes can be joined in such a way that manufacturingtime and cost can be reduced. In various embodiments, one or more spacerstructures can be arranged between components of a joint, e.g., betweena node and a tube, between two nodes, between a tube and aninterconnect, etc., in order to prevent these components from contactingeach other. In this way, for example, nodes and tubes made of dissimilarmaterials can be joined in a way that can help reduce or prevent thedifferent materials from reacting with each other. For example, nodesand tubes made of different metals may be joined in a way that helpsreduce or prevent galvanic corrosion. This can, for example, expand theavailable options for the materials used in the different components ofthe joint, which may allow selection of more suitable materials forindividual components. In turn, the expanded material options may allowbetter performance, durability, weight savings, cost, etc., of thejoint.

FIGS. 2A-E illustrate exemplary nodes, tube, and interconnect that forma joint 200 (shown in FIGS. 2D and 2E). This example configurationincludes a spacer structure formed between the components of the joint.In this example, the spacer structure includes an arrangement of sealsthat create a sealed space between components and an adhesive that isinjected into the sealed space. By sealing the space, the seals canprevent the adhesive from leaking out from the sealed space, which mayallow the joint to be formed more efficiently and may provide acleaner-looking joint. In addition, the seals can keep the componentsseparated at a desired distance while the adhesive cures. The seals canalso help protect the adhesive from the environment, e.g., air, water,etc., which may reduce damage or degradation of the adhesive caused byenvironmental factors. Depending on the composition and design of theseals, the seals may provide other benefits to the spacer structure oncethe adhesive is cured, such as adding rigidity, flexibility, durability,etc., to the structure. The distance created by the spacer structurebetween the components can be designed to prevent or reduce a reactionbetween the components, such as galvanic corrosion.

FIG. 2A illustrates various components of joint 200 prior to assemblyand joining. In particular, a first node 201, a tube 203, and a secondnode 205 can be joined by an interconnect 206. First node 201, secondnode 205, and interconnect 206 can each include notches 208 for thepositioning of seals 207. Prior to assembly, as shown in FIG. 2A, one ofthe seals 207 can be positioned in notch 208 on shaft 211 ofinterconnect 206. In various embodiments, seals 207 can be rubber seals,such as rubber rings, which can compress to form a seal between adjacentcomponents once the joint is assembled. In various embodiments, sealsmay be made of other materials, such as plastic, metal, etc.

Interconnect 206 can include a base 209 and a shaft 211. Shaft 211 caninclude an outer surface 212. When the components of joint 200 areassembled, various surfaces of first node 201, tube 203, second node205, and interconnect 206 can be positioned close to each other in theinterior of the joint. These surfaces may be referred to as jointsurfaces. Base 209 can include a joint surface 213 and a joint surface215. A channel 217 can run through interconnect 206, with one end of thechannel including an opening 219 in base 209, and another end of thechannel including an opening 221 in shaft 211. In various embodiments,channel 217 can include openings at other locations on interconnect 206,can include more than two openings, can include one or more openings ateach of joint surfaces 213 and 215, can include openings arranged in aneven distribution around a cross-sectional surface of the interconnect,and many other possible configurations. As mentioned above, one of seals207 can be positioned within notch 208, which may run around theperimeter of shaft 211. In this regard, seal 207 may be positioned oninterconnect 206 prior to the interconnect being moved into position forassembly, for example.

A joint surface 223 of first node 201 and a joint surface 213 ofinterconnect 206 can be complementary surfaces. In other words, jointsurfaces 213 and 223 can complement each other so that the surfaces fittogether. For example, joint surface 213 can include a portion of ahemispherical surface, and joint surface 223 can include a complementaryportion of an inverse-hemispherical surface.

Tube 203 can include an inner surface 227, a joint surface 229, and ajoint surface 231. Joint surface 229 can be shaped to fit with a jointsurface 225 of first node 201. In this example, joint surface 229 is atapered surface. In various embodiments, joint surface 229 can include aflat, cross-sectional surface at the end (i.e., in the case that thetube were cut perpendicular to the length axis). In various embodiments,tube 203 can be a straight cylinder with no taper, and joint surface 229can include a portion of the outer surface of tube 203 without taper. Invarious embodiments, joint surface 229 can be smooth, threaded, etc.Joint surface 225 of first node 201 can be a complementary shape ofjoint surface 229.

Inner surface 227 of tube 203 can be a straight cylindrical surface, forexample. In various embodiments, inner surface 227 can include a taperedcylindrical surface, a threaded surface, etc. Inner surface 227 can beshaped to fit with interconnect 206, and in particular, may be shaped tofit with outer surface 212 of shaft 211 of the interconnect.

Similarly, second node 205 can include a joint surface 233 that isshaped to fit with joint surface 231 of tube 203, and can include ajoint surface 235 that is shaped to fit with joint surface 215 ofinterconnect 206.

Joint surface 223 can include one of notches 208 and joint surface 225can include another one of notches 208. Likewise, joint surface 233 caninclude one of notches 208 and joint surface 235 can include another oneof notches 208.

FIG. 2B illustrates how first node 201 and second node 205 can bepositioned so that seals 207 can be inserted into notches 208. Inparticular, one of seals 207 can be inserted in notches 208 in jointsurfaces 225 and 233, and another one of seals 207 can be inserted inthe notches in joint surfaces 223 and 235. For example, these seals 207may also be rubber seals, such as rubber rings. In this embodiment,seals 207 that are inserted in notches 208 in first node 201 and secondnode 205 are thicker than the seal inserted into the notch around shaft211 of interconnect 206. The thicker seals can create a desired distancebetween components made of different materials. In this example, firstnode 201 and second node 205 can be made of a first metal, and tube 203and interconnect 206 can be made of a second metal. The thicker sealscan create a larger distance between the first-metal components (i.e.,the nodes) and the second-metal components (i.e., the tube andinterconnect), as will be described in more detail below with respect toFIG. 2D.

FIG. 2C illustrates all of the components of joint 200 assembledtogether prior to joining. In particular, FIG. 2C illustrates how thevarious joint surfaces of the components complement each other and fittogether.

FIG. 2D illustrates the various components of joint 200 assembled andjoined. In particular, an adhesive 237 can be injected into channel 217.Adhesive 237 can fill in the spaces in between the joint surfaces 213and 223, 225 and 229, 231 and 233, 235 and 215, and in between innersurface 227 of tube 203 and outer surface 212 of interconnect 206. Inthis example, seals 207 can contain adhesive 237 to the spaces betweenthe joint surfaces. In this way, for example, first node 201, tube 203,and second node 205 can be joined together with interconnect 206.Moreover, seals 207 may allow adhesive 237 to be injected moreforcefully without concern for excess adhesive leaking out of the joint,which may allow quicker assembly. Similarly, seals 207 may allow for aless viscous adhesive to be used, which may allow a wider range ofadhesives to be used.

As FIG. 2D illustrates, seals 207 and adhesive 237 can create a spacerstructure 239 that can separate the various components of joint 200. Inparticular, the thicker seals separate the first-metal components (i.e.,the nodes) and the second-metal components (i.e., the tube andinterconnect) by a larger distance, while the thinner seal around theinterconnect's shaft separates the tube and interconnect by a smallerdistance. In this way, for example, components made of dissimilar metalscan be separated by a larger distance to reduce or prevent galvaniccorrosion, while components made of the same (or similar) metal can bespaced more closely together, which may allow a more rigid structure.

Spacer structures can be configured to meet the design requirements ofthe joints. For example, spacer structures can create a variety ofseparation distances between components of joints. In variousembodiments, spacer structures can create larger separation distancesbetween components in order to reduce or prevent a reaction between thecomponents. For example, a larger separation distance may be helpful toreduce or prevent galvanic corrosion, particularly in joints that haveadjacent components with very different electrode potentials. Spacerstructures can be made of a variety of materials, such as rubber,adhesive, plastic, metal, etc. The material composition of a spacerstructure can be designed to provide a particular benefit, such asproviding flexibility of movement among joint components, providingrigidity to reduce or prevent movement among joint components, makingthe joint water resistant or waterproof, making the joint resistant toother substances, such as oil, grease, dirt, etc. In variousembodiments, for example, the structural design and material compositionof the spacer structure can allow the joint to fail gracefully, whichmay allow the joint to be used as part of a crush zone by allowing aportion of the crash energy to be dissipated in a controlled, partialfailure of the joint.

FIG. 2E shows a perspective view of joint 200. As FIG. 2E illustrates,the joining technique can allow the exposed surface of base 209 (at thebottom of the base as shown in the FIGS. 2A-D) to be flush with thebottom surfaces of first node 201 and second node 205, while at the sametime allowing the surfaces of the base, first node, and second node tobe separated by a gap 241 (also shown in FIG. 2D) due to spacerstructure 239. In this way, for example, the joining technique canresult in a smooth, flat surface that has an appealing look and thatreduces the need for post-processing, such as sanding, finishing, etc.,and therefore, nodes and tubes can be joined in such a way thatmanufacturing time and cost can be reduced.

First node 201 and second node 205, as well as one or both of tube 203and interconnect 206 can be fabricated by additive manufacturing. Forexample, first node 201, second node 205, and interconnect 206 can beadditively manufactured. In some embodiments, first node 201, secondnode 205, and interconnect 206 can be additively manufactured in thesame print run. In various embodiments, additive manufacturing can takeadvantage of the complementary surfaces of interconnect 206 and firstand second nodes 201 and 205 by spacing fabricating these structuresclose together with the complementary surfaces adjacent to each other.In this way, for example, these structures can allow a more efficientadditive manufacturing process because they are able to be packedtogether more closely, thus increasing the yield of each printing run.

FIGS. 3A-D illustrate exemplary nodes, tube, and interconnect that forma joint 300 (shown in FIGS. 3C and 3D). FIG. 3A illustrates variouscomponents of joint 300 prior to assembly and joining. In particular, afirst node 301, a tube 303, and a second node 305 can be joined by aninterconnect 307. Interconnect 307 can include a base 309 and a shaft311. Shaft 311 can include an outer surface 312. Base 309 can include ajoint surface 313 and a joint surface 315. A channel 317 can run throughinterconnect 307, with one end of the channel including an opening 319in base 309, and another end of the channel including an opening 321 inshaft 311. In various embodiments, channel 317 can include openings atother locations on interconnect 307, can include more than two openings,can include one or more openings at each of joint surfaces 313 and 315,can include openings arranged in an even distribution around across-sectional surface of the interconnect, and many other possibleconfigurations.

First node 301 can include a joint surface 323 and a joint surface 325.Joint surface 323 of first node 301 and joint surface 313 ofinterconnect 307 can be complementary surfaces. In other words, jointsurfaces 313 and 323 can complement each other so that the surfaces fittogether. For example, joint surface 313 can include a portion of ahemispherical surface, and joint surface 323 can include a complementaryportion of an inverse-hemispherical surface.

Tube 303 can include an inner surface 327, a joint surface 329, and ajoint surface 331. Joint surface 329 can be shaped to fit with jointsurface 325 of first node 301. In this example, joint surface 329 is atapered surface. In various embodiments, joint surface 329 can include aflat, cross-sectional surface at the end (i.e., as if the tube were cutperpendicular to the length axis). In various embodiments, tube 303 canbe a straight cylinder with no taper, and joint surface 329 can includea portion of the outer surface of tube 303 without taper. In variousembodiments, joint surface 329 can be smooth, threaded, etc. Jointsurface 325 of first node 301 can be a complementary shape of jointsurface 327.

Inner surface 327 of tube 303 can be a straight cylindrical surface. Invarious embodiments, inner surface 327 can include a tapered cylindricalsurface, a threaded surface, etc. Inner surface 327 can be shaped to fitwith interconnect 307, and in particular, may be shaped to fit withouter surface 312 of shaft 311 of the interconnect.

Similarly, second node 305 can include a joint surface 333 that isshaped to fit with joint surface 331 of tube 303, and can include ajoint surface 335 that is shaped to fit with joint surface 315 ofinterconnect 307.

FIG. 3B illustrates the various components of joint 300 assembledtogether prior to joining. In particular, FIG. 3B illustrates how thevarious joint surfaces of the components complement each other and fittogether.

FIG. 3C illustrates the various components of joint 300 assembled andjoined. In particular, an adhesive 337 can be injected into channel 317.Adhesive 337 can fill in the spaces in between the joint surfaces 313and 323, 325 and 329, 331 and 333, 335 and 315, and in between innersurface 327 of tube 303 and outer surface 312 of interconnect 307. Inthis way, for example, first node 301, tube 303, and second node 305 canbe joined together with interconnect 307.

FIG. 3D shows a perspective view of joint 300. As FIG. 3D illustrates,the joining technique can allow the exposed surface of base 309 (at thebottom of the base as shown in the figures) to be flush with thesurfaces of first nodes 301 and 305. In this way, for example, thejoining technique can result in a smooth, flat surface that has anappealing look and that reduces the need for post-processing, such assanding, finishing, etc., and therefore, nodes and tubes can be joinedin such a way that manufacturing time and cost can be reduced.

First node 301 and second node 305, as well as one or both of tube 303and interconnect 307 can be fabricated by additive manufacturing. Forexample, first node 301, second node 305, and interconnect 307 can beadditively manufactured. In some embodiments, first node 301, secondnode 305, and interconnect 307 can be additively manufactured in thesame print run. In various embodiments, additive manufacturing can takeadvantage of the complementary surfaces of interconnect 307 and firstand second nodes 301 and 305 by spacing fabricating these structuresclose together with the complementary surfaces adjacent to each other.In this way, for example, these structures can allow a more efficientadditive manufacturing process because they are able to be packedtogether more closely, thus increasing the yield of each printing run.

FIGS. 4A-D illustrate exemplary nodes, tube, and interconnect that forma joint 400 (shown in FIGS. 4C and 4D). FIG. 4A illustrates variouscomponents of joint 400 prior to assembly and joining. In particular, afirst node 401, a tube 403, and a second node 405 can be joined by aninterconnect 407. Interconnect 407 can include a base 409 and a shaft411. In this regard, interconnect 407, first node 401, and second node405 have various joint surfaces, which are not labeled for the sake ofclarity. Interconnect 407 can also include a flange 413. Flange 413 canprovide additional joint surface area to connect tube 403 andinterconnect 407. In this regard, flange 413 can create a double shearconnection 419 between tube 403 and interconnect 407.

First node 401, second node 405, and interconnect 407 can include seals415 positioned within notches 416, either before positioning forassembly (e.g., the seals positioned in the notches on the interconnect,or after a partial assembly (e.g., the seals positioned in the notcheson the first and second nodes). For example, seals 415 can be rubberseals, such as rubber rings, which can compress to form a seal betweenadjacent components once the joint is assembled. In various embodiments,seals such as seals 415 can be part of a spacer structure that canprevent portions of various components from contacting each other. Achannel 417 can run through interconnect 407. In various embodiments, achannel such as channel 417 can include openings at various locations oninterconnect 407, can include more than two openings, can includeopenings arranged in an even distribution around a cross-sectionalsurface of the interconnect, and many other possible configurations. Inthis example, channel 417 can include two branches such that an adhesive421 injected into the channel can be emerge at two different jointsurface locations. This can allow adhesive 421 to reach spaces betweenjoint surfaces that are separated by seals 415, for example. After firstnode 401, tube 403, second node 405, and interconnect 407 are broughttogether, adhesive 421 can be injected into channel 417 to join nodesand tube together with the interconnect.

As shown in FIG. 4C, first node 401, tube 403, second node 405, andinterconnect 407 can include multiple joint surfaces that can complementeach other so that the surfaces fit together. It should be noted thatother configurations of joint surfaces are possible, for example, tube403 can include a tapered surface that fits with a likewise taperedopening created by flange 413 in various embodiments. In variousembodiments, various joint surfaces can be smooth, threaded, etc.

FIG. 4B illustrates the various components of joint 400 assembledtogether prior to joining. In particular, FIG. 4B illustrates how thevarious joint surfaces of the components complement each other and fittogether.

FIG. 4C illustrates the various components of joint 400 assembled andjoined. In particular, adhesive 421 can be injected into channel 417 andcan fill in the spaces in between first node 401 and interconnect 407,between interconnect 407 and tube 403, and between second node 405 andinterconnect 407. In this way, for example, first node 401, tube 403,and second node 405 can be joined together with interconnect 407.

FIG. 4D shows a perspective view of joint 400. The joining technique ofFIGS. 4A-D can allow the exposed surface of base 409 (at the bottom ofthe base as shown in the figures) to be flush with the surfaces of firstnodes 401 and 405. In this way, for example, the joining technique canresult in a smooth, flat surface that has an appealing look and thatreduces the need for post-processing, such as sanding, finishing, etc.,and therefore, nodes and tubes can be joined in such a way thatmanufacturing time and cost can be reduced.

One or more of first node 401, tube 403, second node 405, andinterconnect 407 can be fabricated by additive manufacturing. Forexample, first node 401, second node 405, and interconnect 407 can beadditively manufactured. In some embodiments, first node 401, secondnode 405, and interconnect 407 can be additively manufactured in thesame print run. In various embodiments, additive manufacturing can takeadvantage of the complementary surfaces of interconnect 407 and firstand second nodes 401 and 405 by spacing fabricating these structuresclose together with the complementary surfaces adjacent to each other.In this way, for example, these structures can allow a more efficientadditive manufacturing process because they are able to be packedtogether more closely, thus increasing the yield of each printing run.

FIGS. 5A-C illustrate exemplary nodes, tube, and interconnect that forma joint 500 (shown in FIGS. 5B and 5C). FIG. 5A illustrates variouscomponents of joint 500 prior to assembly and joining. In particular, afirst node 501, a tube 503, and a second node 505 can be joined by aninterconnect 507. Interconnect 507 can be an annular structure thatincludes a flange 509. In this regard, FIGS. 5A-B show two portions(also referred to as elements herein) of interconnect 507, and it shouldbe understood that the two portions are part of the same structure thatis the interconnect. The two elements of interconnect 507 form a slot510 in between.

First node 501 can include a bracket 511, and second node 505 caninclude a bracket 513. Brackets 511 and 513 can be configured to supportflange 509. Brackets 511 and 513 can have, for example, an arc shapethat matches the annular shape of flange 509. Interconnect 507 caninclude sealing components, such as seals 515 that can be seated innotches 517. The sealing components can be included on flange 509 and ona surface of slot 510, for example. In various embodiments, seals suchas seals 515 can be part of a spacer structure that can prevent portionsof various components from contacting each other.

FIG. 5B illustrates the various components of joint 500 assembled andjoined. In particular, tube 503 can be inserted into slot 510, withadhesive 519 being applied in the spaces between sealing components. Inthis regard, seals 515 can contain adhesive 519 to provide a morecontrolled bonding area. Seals 515 can be, for example, rubber seals oranother type of seal. Thus, as shown in FIG. 5B, interconnect 507 can bejoined to first node 501, tube 503 can be joined to the interconnect,and the interconnect can be joined to second node 505. Brackets 511 and513 can provide additional support of interconnect 507 by bracketingflange 509, and the brackets and flange structure can provide a failsafeconnection between the interconnect and the first and second nodes incase adhesive 519 fails. In this regard, joint 500 can provide for agraceful failure of the node-interconnect connection.

FIG. 5C shows a perspective view of joint 500. As FIG. 5C illustrates,brackets 511 and 513 come together during assembly to completely coverthe outer edge of interconnect 507

It is noted that one or more of first node 501, tube 503, second node505, and interconnect 507 can be fabricated by additive manufacturing.For example, first node 501, second node 505, and interconnect 507 canbe additively manufactured. In some embodiments, first node 501, secondnode 505, and interconnect 507 can be additively manufactured in thesame print run. In various embodiments, additive manufacturing can takeadvantage of the complementary surfaces of interconnect 507 and firstand second nodes 501 and 505 by spacing fabricating these structuresclose together with the complementary surfaces adjacent to each other.In this way, for example, these structures can allow a more efficientadditive manufacturing process because they are able to be packedtogether more closely, thus increasing the yield of each printing run.

FIGS. 6A-D illustrate an exemplary node including a connection portionto connect to a tube to form a joint 600 (shown in FIG. 6D). FIG. 6Aillustrates various components of joint 600 prior to assembly andjoining. In particular, a node 601 can include an inner portion 603 andan outer portion 605 at one end. Inner portion 603 and outer portion 605can form an annular gap 607 in node 601. In various embodiments, innerportion 603 can have a disk shape, and outer portion 605 can have a ringshape concentric with the disk shape, such that annular gap 607 includesa circular ring gap that is configured to fit a circular tube, such astube 609. In various embodiments, inner and outer portions 603 and 605can have other shapes, such as square, rectangle, etc., to fit tubeshaving corresponding other shapes. In this example, tube 609 is a carbonfiber tube that includes a cured portion 610 and an uncured portion 611.The carbon fiber of tube 609 is infused with resin in cured portion 610,and the carbon fiber is not infused with resin in uncured portion 611.In other words, the uncured portion has dry carbon fibers that are notbound to each other, i.e., loose fibers.

Node 601 can be, for example, an additively manufactured metalstructure, an additively manufactured plastic structure, a carbon fiberstructure, etc. Seals 612 can be arranged on inner surfaces of annulargap 607. Seals 612 can be, for example, rubber seals or another type ofseal. In various embodiments, seals such as seals 612 can be part of aspacer structure that can prevent a portion of a tube from contactingthe surfaces of the annular gap, for example. Node 601 can also includea first port 613 and a second port 615. First port 613 and second port615 can be channels that each connect a portion of annular gap 607 toexterior surfaces of the node.

FIG. 6B illustrates the various components of joint 600 assembledtogether but not yet joined. In particular, tube 609 can be insertedinto annular gap 607. The loose carbon fibers of uncured portion 611 oftube 609 can splay and flare outward as they move deeper into annulargap 607. Seals 612 can contact tube 609 to form a seal.

FIG. 6C illustrates a method of joining node 601 and tube 609.Specifically, a resin 617 can be injected into first port 613 whilesuction, e.g., a vacuum 619 is applied to second port 615. Vacuum 619draws resin 617 through annular gap 607 and impregnates the loose carbonfibers of uncured portion 611 of tube 609. Resin 617 is allowed to cureto form a carbon fiber bond between node 601 and tube 609.

As seen in FIGS. 6B and C, the diameter of the annular gap can increaseas the distance from the end of node (i.e., the depth of the annulargap) increases, which causes the loose carbon fibers of uncured portion611 to flare out when inserted into the annular gap, creating a flaredportion of tube 609 that is form-fitted to the annular gap.

FIG. 6D illustrates joint 600 after resin 617 cures. When resin 617cures, the portion of the resin that impregnates the loose carbon fibersof tube 609 forms a cured carbon fiber flange 621 that is an integralpart of the tube. Moreover, cured carbon fiber flange is formed in theinterior of, and form-fitted to, annular gap 607, which can increase thestructural integrity of the joint.

The previous description is provided to enable any person skilled in theart to practice the various aspects described herein. Variousmodifications to these exemplary embodiments presented throughout thisdisclosure will be readily apparent to those skilled in the art. Thus,the claims are not intended to be limited to the exemplary embodimentspresented throughout the disclosure, but are to be accorded the fullscope consistent with the language claims. All structural and functionalequivalents to the elements of the exemplary embodiments describedthroughout this disclosure that are known or later come to be known tothose of ordinary skill in the art are intended to be encompassed by theclaims. Moreover, nothing disclosed herein is intended to be dedicatedto the public regardless of whether such disclosure is explicitlyrecited in the claims. No claim element is to be construed under theprovisions of 35 U.S.C. § 112(f), or analogous law in applicablejurisdictions, unless the element is expressly recited using the phrase“means for” or, in the case of a method claim, the element is recitedusing the phrase “step for.”

What is claimed is:
 1. An apparatus, comprising: an additivelymanufactured first node including a first surface; an additivelymanufactured second node including a second surface; a tube; aninterconnect connecting the tube to the first and the second nodes,wherein the interconnect comprises a base and a shaft extending from thebase, and wherein an exposed surface of the base is flush with the firstand the second surfaces when the first node, the second node, the tube,and the interconnect are joined; and a spacer structure arranged betweenand entirely separating three or more of the first node, the secondnode, the tube, and the interconnect.
 2. The apparatus of claim 1,wherein the first and the second nodes are adhered to the base and thetube is adhered to the shaft.
 3. The apparatus of claim 2, wherein thebase comprises a first portion adhered to a complementary portion of thefirst node and a second portion adhered to a complementary portion ofthe second node.
 4. The apparatus of claim 2, wherein the shaft extendsinto the tube and is adhered to the inner surface of the tube.
 5. Theapparatus of claim 1, wherein the interconnect comprises a first elementadhered to the first node and the tube, and a second element adhered tothe second node and the tube.
 6. The apparatus of claim 5, wherein thefirst and the second elements are arranged to form a slot, and whereinthe tube extends through the slot.
 7. The apparatus of claim 5, whereinthe first node comprises a first bracket supporting the first elementand the second node comprises a second bracket supporting the secondelement.
 8. The apparatus of claim 1, further comprising: the spacerstructure arranged between the first node, the second node, the tube,and the interconnect.
 9. The apparatus of claim 8, wherein the spacerstructure includes a seal.
 10. The apparatus of claim 8, wherein thespacer structure includes adhesive.
 11. An apparatus, comprising: anadditively manufactured first node; an additively manufactured secondnode; a tube; an interconnect connecting the tube to the first and thesecond nodes, wherein the interconnect comprises a base and a shaftextending from the base; and a spacer structure arranged between thefirst node, the second node, the tube, and the interconnect, wherein thespacer structure is configured to entirely separate one or more of thefirst node and the second node from one or more of the tube and theinterconnect by a first separation distance, and wherein the spacerstructure is configured to entirely separate the tube from theinterconnect by a second separation distance, the second separationdistance being smaller than the first separation distance.